Researchers at the University of Electronic Science and Technology of China (UESTC) have revealed a new wound dressing that can both monitor a wound and deliver medicine automatically when the tissue shows signs of trouble.
Having seen contributions from West China Hospital of Sichuan University and The Chinese University of Hong Kong, the research describes a 3D printed patch built around microscopic needles with tiny barbs that help the device stay in place during long periods of wear. Chronic wounds, such as diabetic ulcers and pressure sores, are a growing burden in many health systems. They often need frequent inspection, and removing dressings to check healing can itself slow recovery or cause new injury.
The team set out to design a dressing that could stay on the skin, keep watch on the wound’s condition, and respond without waiting for a clinician to intervene.
A closed-loop microneedle wound patch
At the core of the system are two types of high-resolution 3D printed microneedles: solid ones (3D-BMN) that act as electrodes to measure tissue impedance and hollow ones (3D-BHMN) that deliver liquid drugs, both equipped with small, bee-stinger-inspired barbs. In laboratory tests, these barbs helped the needles anchor into an agarose-based dressing model, while the system was evaluated on a gelatin-based skin model covered by such dressings, making the needles harder to dislodge without requiring excessive insertion force.
Impedance is a measure of how tissue resists electrical current, changes with moisture, inflammation, and infection, and previous studies have shown that a drop often accompanies worsening wound conditions.
To improve measurement stability and reproducibility, the researchers coated the sensing needles with layers of silver, silver chloride, and gold nanoparticles, and in experiments using gelatin and agarose gels that mimic skin and wound dressings, the coated needles produced consistent signals across different simulated wound states.
The delivery system uses hollow microneedles connected to a small drug chamber and an ultrasonic atomizer that, when activated, turns liquid medication into a fine mist and drives it through microscopic channels into the tissue. In a standard laboratory diffusion test comparing topical application, hollow microneedles without ultrasound, and ultrasound-assisted microneedles, the ultrasound-assisted setup delivered markedly more of a test dye into the model tissue over 30 minutes than the other two methods.
What sets the platform apart is its closed-loop design: a small control circuit continuously reads impedance from the sensing needles and automatically triggers the atomizer to deliver medication when the value falls below a preset threshold, which can indicate rising inflammation or infection. In calibration tests, the impedance readings were within about a quarter of a percent of reference values, showing that the system operates with reasonable accuracy under laboratory conditions.
Including the barbed needles and drug delivery module, the entire device was fabricated using projection micro stereolithography, with the microneedle structures printed in a single step and later given conductive coatings. The authors note that this approach makes it easier to customize designs for different clinical needs, such as 1300 µm needle lengths, 0.3 mm hollow lumens (with 0.4 mm feeding microchannels in the drug chamber), or different drug chamber sizes.
For now, all the demonstrations were done in vitro using gel models rather than living tissue. That means questions about comfort, long term skin response, infection risk, and real world reliability still need to be answered in animal and human studies. The system also relies on external power and electronics, which would have to be integrated into a practical wearable format.
Even so, the study points toward a future in which wound dressings do more than cover and protect. By combining continuous sensing with automated, localized treatment, such devices could reduce the need for frequent dressing changes and enable earlier intervention when healing goes off track, moving wound care toward systems that react to the body rather than waiting for visible signs of failure.
The rise of 3D printed wound healing
The use of 3D printing for wound healing has been drawing increasing attention as researchers investigate its potential uses in medicine.
For instance, Pusan National University (PNU) researchers developed a bioprinting approach to create functional adipose tissue for wound healing using a hybrid bioink made from 1% adipose-derived decellularized extracellular matrix and 0.5% alginate. The printed fat units were designed to remain under 600 µm in diameter and spaced within 1000 µm to ensure adequate nutrient diffusion and paracrine signaling.
Combined with dermal modules to form a skin substitute and implanted in mice, the constructs accelerated wound closure, improved tissue remodeling and vascularization, and modulated key proteins involved in skin regeneration, outperforming conventional fat grafting.
A few years ago, scientists at RCSI University of Medicine and Health Sciences developed a 3D printable bio-ink by integrating platelet-rich plasma (PRP) into a gelatin-based hydrogel to create regenerative scaffolds for wound healing. PRP was isolated from donor blood, mixed with a photoinitiator and gelatin, and extruded using an Allevi II printer into porous scaffolds that degraded more slowly than pure hydrogel.
The constructs released growth factors over 14 days, with about 10% PRP released and VEGF dispersing fastest. In chick embryo tests, the PRP scaffolds increased vascularization by around 40–50% compared with controls, promoting formation of new blood vessels.
The researchers’ findings are detailed in their paper titled “3D-Printed Barbed Microneedle Electrodes For Biosensing And Drug Delivery In Wound Management.” The research was co-authored by Xinyu Fu, Zhengnan Sun, Jun Gu, Ruiqi Liu, Meng Ma, Xuelei Ma, Yi-Ping Ho, Xiaosheng Zhang and Yi Zhang.
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Featured image shows on-demand drug delivery with impedance feedback via 3D-BMN and 3D-BHMN. Image via UESTC.
